如何生成C#中属性值列表的笛卡尔积？

基于你给出的C#类结构，以下两种方法可以生成所有属性选项的笛卡尔积，并输出你需要的连字符分隔格式。

类结构回顾 #

public class AttributeOption
{
    public Guid Id { get; set; }
    public string Name { get; set; }
}

public class MyAttribute
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public List<AttributeOption> Options { get; set; } = new List<AttributeOption>();
}

方法一：递归实现 #

递归逻辑直观，逐步组合每个属性的选项与剩余属性的笛卡尔积结果：

public static List<string> GenerateCartesianProduct(List<MyAttribute> attributes)
{
    if (attributes == null || attributes.Count == 0)
        return new List<string>();

    var firstAttrOptions = attributes[0].Options.Select(o => o.Name).ToList();
    var remainingProducts = GenerateCartesianProduct(attributes.Skip(1).ToList());

    if (!remainingProducts.Any())
        return firstAttrOptions;

    var result = new List<string>();
    foreach (var option in firstAttrOptions)
    {
        foreach (var product in remainingProducts)
        {
            result.Add($"{option}-{product}");
        }
    }
    return result;
}

方法二：LINQ简洁实现 #

利用Aggregate和SelectMany实现累积式的笛卡尔积计算，代码更紧凑：

public static List<string> GenerateCartesianProductWithLinq(List<MyAttribute> attributes)
{
    var optionLists = attributes.Select(a => a.Options.Select(o => o.Name).ToList()).ToList();

    return optionLists.Aggregate(
        new List<string> { "" },
        (current, next) => current.SelectMany(c => next.Select(n => string.IsNullOrEmpty(c) ? n : $"{c}-{n}")).ToList()
    );
}

使用示例 #

构建测试数据并输出结果：

var attributes = new List<MyAttribute>
{
    new MyAttribute
    {
        Name = "颜色",
        Options = new List<AttributeOption>
        {
            new AttributeOption { Name = "Red" },
            new AttributeOption { Name = "White" },
            new AttributeOption { Name = "Blue" }
        }
    },
    new MyAttribute
    {
        Name = "尺寸",
        Options = new List<AttributeOption>
        {
            new AttributeOption { Name = "Small" },
            new AttributeOption { Name = "Medium" },
            new AttributeOption { Name = "Large" }
        }
    },
    new MyAttribute
    {
        Name = "性别",
        Options = new List<AttributeOption>
        {
            new AttributeOption { Name = "Male" },
            new AttributeOption { Name = "Female" }
        }
    }
};

// 任选一种方法生成结果
var products = GenerateCartesianProduct(attributes);
// 输出格式符合要求的字符串
foreach (var product in products)
{
    Console.WriteLine(product);
}

运行后会输出你需要的格式：

Red-Small-Male
Red-Small-Female
Red-Medium-Male
Red-Medium-Female
Red-Large-Male
Red-Large-Female
White-Small-Male
...

内容的提问来源于stack exchange，提问作者Sam